It is fun to (re) program other peoples designs!

I am about to reprogram my Ericsson GH388. I have managed to do some things but I would be happy if I would get some help.

I have NOT planned do defraud anyone or do anything else illegal. I would just like to be able to play tetris on my mobile phone. (see picture)

Is ther some one who has development kit, programmer or specifications for programming of mobile phones and would like to share that information with me I would be very pleased.

If you happens to have a mobile phone (preferaby GSM) that is broken or out of order by any other reason, I would be very pleased if you would like to give or sell it to me. If you are lucky I might be able to fix it for you.

Build a programming interface for Ericsson 388.

Layout of the mobile phone interface as a gif (11 kb).

This is the layout of a interface for connecting Ericssons phones (318/337/388 probobly also 688&788) to the serial port of a PC. The interface translates the computers RS-232 signals of ±12V to 5V levels.

On the circuitboard you mount a MAX232 or a compatible circuit for example MAX220, MAX222, ICL232, LT1080, LT1081, LT1180 & LT1181. On the reverse side there is space for tantaliumelectrolyt capacitors. 10µF / 16V should be accurate for the most of the circuits (see data charts for detailed information). A 9-pole D-sub female is mounted on the edge of the PCB. The PCB is made to fit a larger model of a standard D-sub housing.

Pictures of the interface PCB

You can also take a look at the schematic or at the pinout of the phone.

In the phone end of the interface I have mounted a connector from a ciggaret lighter socket charger cable. You will need two cables to build one interface.

The charger cables are opened and the connectors pins are moved to the following places (counted from the phones microphone): 6,8,9,11,12. After that the cables in the other end are solderd on the PCB on the pads marked with the corresponding numbers.

I have made the layout a litle bit more advanced to make it able to connect 12V to the phone. This is needed to program the FLASH-PROM that the phones program is located in. This is not needed if your phone is marked with "C A C" or "B A C" after "TYPE" on the back of the phone. These phones can be reprogrammed using only 5V.

The switch can also be used to toggle between "service/programming mode" and "normal mode". Try it out yourself.

DISCLAMER:
It is totally up to you to connect anything to your mobile phone and/or computer. I do not take any responsibility for the correctness in the information provided here. If anything should go wrong you can NOT hold me or anyone else than yourself responsibel for the damage.

It is very easy to permanently damage your mobile phone when using this programming interface, I will not take any responsibility for any damage that occur when using the information presented here.

I have not planned to defraud someone or try to call for free or any thing like that. If you write me a email asking how to defraud someone or how to make calls for free your mail will imediatly be redirected to /dev/null up on reception.

Here you can download postscript files of the layout (scale 1:1 and 2:1) :

Postscript version of the layout

ERIINTFC.ZIP

15 kb

Links to other things

• Joakims page about GH337.
  
• A program written by Diomidis Spinellis for the GH388.
  This is a link to his homepage
  
• Matthews Ericssons secrets
  
• L0phts radiophones page about Ericsson 388
• Arians Ericsson GA628 info.
• Some things about Service/Programming mode on the 388
• Janus page about Motorola phones and other stuff

I have also succeeded in reading out parts of the memory of a Ericsson 388. There is a Z80 in Ericssons phones and I have with some success been able to disassemble the objectcode. The phone has got a smal realtime operating system called OS80 and the source is written in C. Since the code is copyright protected by Ericsson Mobile Communications AB it is not presented here. But you can easily read it out yourself.

This is a SALT scrip to readout the program of the phone. It is not fully tested but I guess it works. It reads out the whole contents of the phones program and translate it into motorola s hex (the download format when the flash is reprogrammed). READOUT.SLT
Like I sed before: I cant distribute any copyright protected material, so please read out the code yourself.

If you would like to help me writing script or program for the phone or the PC please write me a mail. You can also send me a mail if you got any cool pices of code...

If there is someone who has got the source code or would like to disassemble with me so are you also welcome to send me a mail.

Information wants to be free!!!

Source : web.archive.org